Stihl BR 400 Gas Cap spitting fuel

hammmerhead

LawnSite Senior Member
Location
ozarks
Posted this in the repair section, but no responses.

My cap is starting to spit fuel out the two small vent holes in the cap. I pulled it apart and it there was no trash visible. Im assuming that high density fiber filter in the center is saturated and causing the issue.

Is there an updated cap for this old blower or has anyone had this issue?

Thanks guys
 

Danscapes

LawnSite Senior Member
Location
Cincinnati, Ohio
There was a recall on these JUNK AZZ caps. As usual EPA mandates end up screwing the end user. Take all your handhelds to your dealer and they will replace all the caps with "better" ones. :hammerhead: If I could find a bunch of the old style caps I would rip all mine off and put the old ones back on.
 

Ridin' Green

LawnSite Fanatic
Location
Michigan
There was a recall on these JUNK AZZ caps. As usual EPA mandates end up screwing the end user. Take all your handhelds to your dealer and they will replace all the caps with "better" ones. :hammerhead: If I could find a bunch of the old style caps I would rip all mine off and put the old ones back on.
This isn't correct, at least as applies to the BR400. It uses the old screw on caps. Some of the newest BR420's may have the new cap that sucked, but the 400's should all have the screw on cap.

The only time mine have ever started spitting was when the tank was sitting where the sun could heat the fuel and the vapors expanded too much and started doing what yours is doing, and it's usually because the vent holes are either plugged, or not open enough to allow it to vent properly. If the interior lining is worn out, I'd just go to the dealer and get a new one.

BTW, all the new style caps that were replaced by the even newer style caps are now being replaced with the old original style screw caps. I was at my dealer's yesterday looking at equipment, and noticed that Stihl has two different style of screw on caps that they are using on the exact same model of machines. They were sitting there side by side with the latest edition of the "new" style quick release caps as well. What goes around comes around I guess:rolleyes:
 

mattfromNY

LawnSite Bronze Member
Location
Central NY
Your dealer will know which ones qualify for replacement. There is a letter cast into the bottom of the black plastic part on the cap. This will tell the dealer if the cap is to be replaced under the recall or not. If you bought the machine new, you should have received a 'service bulletin' letter in the mail from Stihl. (Unless your dealer never warranty-registered the machine)
 
OP
hammmerhead

hammmerhead

LawnSite Senior Member
Location
ozarks
Well I replaced the cap and its still doing it after I ruin it for 5-10 minutes. Does anyone know if this tank has a separate vent line or something that could be clogged. I havent messed with it or tore into it yet, but I only noticed a fuel line coming out of the tank going to the carb. The tank is obviously over pressurizing for some reason. I know its something simple cause the thing has worked flawlessly for a decade. Maybe someone that has "been there, done that" will chime in.
 

Ridin' Green

LawnSite Fanatic
Location
Michigan
When it's this warm out, I have learned to not fill my tanks all the way to prevent the chance of this happening. I have one that is new that will spit a little gas when it gets like this out, but if I leave about a half inch of air space for the gas to expand, it doesn't spit anymore. Why yours is doing it now, when it didn't before is strange. Maybe it hasn't been as warm as this summer since you owned it? I really believe that the ethanol in fuel causes most of these issues in one way or another.
 
OP
hammmerhead

hammmerhead

LawnSite Senior Member
Location
ozarks
When it's this warm out, I have learned to not fill my tanks all the way to prevent the chance of this happening. I have one that is new that will spit a little gas when it gets like this out, but if I leave about a half inch of air space for the gas to expand, it doesn't spit anymore. Why yours is doing it now, when it didn't before is strange. Maybe it hasn't been as warm as this summer since you owned it? I really believe that the ethanol in fuel causes most of these issues in one way or another.
Thanks Ridin green. It is wierd, because it does it if the tank is half or 1/4 full...it doesnt matter....and its been doing this since winter! I was thinking there has to be some sort of vent for the tank that is clogged or something is pressurizing it. It seems there would have to be a real vent for the tank because I only see one fuel feed line coming out....but I really havent taken a really close look yet. I know there were a few peeps having this issue, but I have not seen where anyone has come up with the fix. BTW, my dealer ordered the updated cap and it did the same thing in just a few minutes of operation.
 

Ridin' Green

LawnSite Fanatic
Location
Michigan
I wish I has the answer for you, but..........

If you do get it sorted out though, I'd like to hear what it was, and prolly so would many others here.:)
 

herler

LawnSite Fanatic
I don't see the fuel cap being the problem, to my understanding those don't have vents, at least not on hand helds... I am thinking the fuel is spitting elsewhere and it looks like it's coming out of the fuel cap, I would check and probably replace the fuel lines themselves, those can leak and have cracks that aren't visible until the lines have been physically removed from the unit, especially those corrugated looking ones... I'd be willing to bet that's where your fuel leak is coming from, either way if you've had the unit for more than 4-5 years it likely wouldn't hurt to replace them and I think they're replaced as a set.
 

Ridin' Green

LawnSite Fanatic
Location
Michigan
I don't see the fuel cap being the problem, to my understanding those don't have vents, at least not on hand helds... I am thinking the fuel is spitting elsewhere and it looks like it's coming out of the fuel cap, I would check and probably replace the fuel lines themselves, those can leak and have cracks that aren't visible until the lines have been physically removed from the unit, especially those corrugated looking ones... I'd be willing to bet that's where your fuel leak is coming from, either way if you've had the unit for more than 4-5 years it likely wouldn't hurt to replace them and I think they're replaced as a set.
ALL fuel caps for handheld equipment have vents in them now, and have for years. They have to to avoid having fuel expand from heat and spray out all over you when you open the cap. You can't always see the vent at a glance, but it's there. My newer Husky 223L will vent fuel out through the two small vent holes if the gas is filled to the top in the tank and it's above about 70 degrees outside.
 

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